Before we can properly configure the Duet with RepRapFirmware, we must gather a list of parameters that define the mechanical operation of the printer itself. This information can be found in multiple places and will vary from printer to printer.

The rest of the guide will go through each page and describe what we need to change to match the Ender 3.

Only changed values will be listed. Match your values to those shown in the screen shots.

At the end we will download a zip file that will replace the /sys folder on the SD card. This folder contains all the configuration files that define how the Maestro is configured and how it behaves during certain operations like homing.

The General Tab is used to define a few basic starting values like which board you are using, whether to use resume on power loss functionality, the size of your build volume, and what kinematics your printer uses.

These values are found in the Marlin Configuration.h. Note that some slight changes have been made to bring it more in line with standard RepRapFirmware values.

Note that the Extruder microsteps have been set to x128 in the image. this is to increase the resolution of the extruder drive, which is rather low do to being an ungeared direct drive extruder. This is optional. The default x16 value also works and leads to a steps per mm value of ~96. Exact value to be calibrated later.

Give your printer a name that will show up on your network and set a password if you wish.

In order to connect to the web interface, we need to reliably know the IP address of the Duet. You have two options for this: Static IP versus Dynamic IP

1. Set a static IP address in the config file of the Duet that falls within your network range, but which isn’t already used, or likely to be used by your router for another device in the future.

2. Use DHCP to let the router choose a suitable IP address for the Duet and then use the Router control panel to reserve that IP address for future use by the Duet.

For this guide, we will be using DHCP to get an IP address from the Router as it is best practice to use DHCP to assign the address and then use the router control panel to assign the address permanently with a DHCP reservation. This prevents any possible future IP conflicts with another device on the network.

The steps for setting up a reservation will depend on your model of router and is outside the scope of this guide, but instructions can usually be found in the manual for the router.

This will have the fans turn off at startup, setup Fan0 for the part cooling fan, setup Fan1 for the hot end fan to turn on automatically at 45c, and Fan2 as the case fan which will turn on automatically when either the bed or the hot end reach 45c, which is basically during a print.

In my testing I found that the fans are quietest and start spinning most reliably with 20hz frequency. Other fans may behave differently. If your fans have a high-pitched whine, or don’t reliably spin at low speeds, try experimenting with the fan frequency. Values from 10 to 30000 are usable. 500 is default.

The Duet board will come from the factory with a recent firmware version installed already, but as part of this guide we will go through the process of updating it so that we have a known stable recent version.